Proteases are widely used as ingredients in commercial detergents to improve the detergency towards proteinaceous soiling. Further information on this may be found in the article "How Enzymes got into Detergents", vol. 12, Developments in Industrial Microbiology, a publication of the Society for Industrial Microbiology, American Institute of Biological Sciences, Washington, D.C. 1971, by Claus Dambmann, Poul Holm, Villy Jensen and Mogens Hilmer Nielsen, and in P.N. Christensen, K. Thomsen and S. Branner: "Development of Detergent Enzymes", paper presented on 9 October 1986 at the 2nd World Conference on Detergents held in Montreaux, Switzerland.
As indicated in said references, trypsin preparations were previously used in detergents, but since the 1960's alkaline Bacillus proteases have been used almost exclusively for this purpose, and in this period large efforts have been devoted to the development of microbial proteases with improved detergency. Detergents comprising alkaline Bacillus proteases are described e.g. in GB 1,342,784 and GB 1,356,130.
It is known that whereas pure trypsin is very specific hydrolyzing only a few peptide bonds in any given protein, the commonly used Bacillus proteases have a broad specificity and thus hydrolyze many bonds in a given substrate.
In the search for improved proteases it has been assumed that such a protease should have the broadest possible substrate specificity, i.e. it should be able to hydrolyze as many bonds as possible in the protein soiling.
Thus, M. Minagawa, Osaka Shiritsu Daigaku Seikatsu Kagaku-bu Kiyo, vol. 23, pp. 65-74 (1975) states on p. 68: "The type of protease adapted for use in the removal of protein stains must have a wide spectrum of substrate specificity capable of degrading the peptide bond, indiscriminately."